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<div class="titlepage"><div><div><h5 class="title">
<a name="spirit.qi.reference.operator.permutation"></a><a class="link" href="permutation.html" title="Permutation Parser (a ^ b)">Permutation
          Parser (<code class="computeroutput"><span class="identifier">a</span> <span class="special">^</span>
          <span class="identifier">b</span></code>)</a>
</h5></div></div></div>
<h6>
<a name="spirit.qi.reference.operator.permutation.h0"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.description"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.description">Description</a>
          </h6>
<p>
            The permutation operator, <code class="computeroutput"><span class="identifier">a</span>
            <span class="special">^</span> <span class="identifier">b</span></code>,
            matches one or more operands (<code class="computeroutput"><span class="identifier">a</span></code>,
            <code class="computeroutput"><span class="identifier">b</span></code>, ... etc.) in any order:
          </p>
<pre class="programlisting"><span class="identifier">a</span> <span class="special">^</span> <span class="identifier">b</span> <span class="special">^</span> <span class="special">...</span>
</pre>
<p>
            The operands are the elements in the permutation set. Each element in
            the permutation set may occur at most once, but not all elements of the
            given set need to be present. Note that by this definition, the permutation
            operator is not limited to strict permutations.
          </p>
<p>
            For example:
          </p>
<pre class="programlisting"><span class="identifier">char_</span><span class="special">(</span><span class="char">'a'</span><span class="special">)</span> <span class="special">^</span> <span class="char">'b'</span> <span class="special">^</span> <span class="char">'c'</span>
</pre>
<p>
            matches:
          </p>
<pre class="programlisting"><span class="string">"a"</span><span class="special">,</span> <span class="string">"ab"</span><span class="special">,</span> <span class="string">"abc"</span><span class="special">,</span> <span class="string">"cba"</span><span class="special">,</span> <span class="string">"bca"</span> <span class="special">...</span> <span class="identifier">etc</span><span class="special">.</span>
</pre>
<h6>
<a name="spirit.qi.reference.operator.permutation.h1"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.header"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.header">Header</a>
          </h6>
<pre class="programlisting"><span class="comment">// forwards to &lt;boost/spirit/home/qi/operator/permutation.hpp&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">qi_permutation</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
</pre>
<p>
            Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>.
          </p>
<h6>
<a name="spirit.qi.reference.operator.permutation.h2"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.model_of"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.model_of">Model of</a>
          </h6>
<div class="blockquote"><blockquote class="blockquote"><p>
              <a class="link" href="../parser_concepts/naryparser.html" title="NaryParser"><code class="computeroutput"><span class="identifier">NaryParser</span></code></a>
            </p></blockquote></div>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl class="variablelist">
<dt><span class="term"><code class="computeroutput"><span class="identifier">a</span></code>, <code class="computeroutput"><span class="identifier">b</span></code></span></dt>
<dd><p>
                  A <a class="link" href="../parser_concepts/parser.html" title="Parser"><code class="computeroutput"><span class="identifier">Parser</span></code></a>
                </p></dd>
</dl>
</div>
<h6>
<a name="spirit.qi.reference.operator.permutation.h3"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.expression_semantics"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.expression_semantics">Expression
            Semantics</a>
          </h6>
<p>
            Semantics of an expression is defined only where it differs from, or
            is not defined in <a class="link" href="../parser_concepts/naryparser.html" title="NaryParser"><code class="computeroutput"><span class="identifier">NaryParser</span></code></a>.
          </p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                    <p>
                      Expression
                    </p>
                  </th>
<th>
                    <p>
                      Semantics
                    </p>
                  </th>
</tr></thead>
<tbody><tr>
<td>
                    <p>
                      <code class="computeroutput"><span class="identifier">a</span> <span class="special">^</span>
                      <span class="identifier">b</span></code>
                    </p>
                  </td>
<td>
                    <p>
                      Match <code class="computeroutput"><span class="identifier">a</span></code> or
                      <code class="computeroutput"><span class="identifier">b</span></code> in any order.
                      Each operand may match zero or one time as long as at least
                      one operand matches.
                    </p>
                  </td>
</tr></tbody>
</table></div>
<h6>
<a name="spirit.qi.reference.operator.permutation.h4"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.attributes"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.attributes">Attributes</a>
          </h6>
<p>
            See <a class="link" href="../../quick_reference/compound_attribute_rules.html#spirit.qi.quick_reference.compound_attribute_rules.notation">Compound
            Attribute Notation</a>.
          </p>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                    <p>
                      Expression
                    </p>
                  </th>
<th>
                    <p>
                      Attribute
                    </p>
                  </th>
</tr></thead>
<tbody><tr>
<td>
                    <p>
                      <code class="computeroutput"><span class="identifier">a</span> <span class="special">^</span>
                      <span class="identifier">b</span></code>
                    </p>
                  </td>
<td>
                    <p>
</p>
<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">a</span><span class="special">:</span> <span class="identifier">A</span><span class="special">,</span> <span class="identifier">b</span><span class="special">:</span> <span class="identifier">B</span> <span class="special">--&gt;</span> <span class="special">(</span><span class="identifier">a</span> <span class="special">^</span> <span class="identifier">b</span><span class="special">):</span> <span class="identifier">tuple</span><span class="special">&lt;</span><span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">A</span><span class="special">&gt;,</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">B</span><span class="special">&gt;</span> <span class="special">&gt;</span>
<span class="identifier">a</span><span class="special">:</span> <span class="identifier">A</span><span class="special">,</span> <span class="identifier">b</span><span class="special">:</span> <span class="identifier">Unused</span> <span class="special">--&gt;</span> <span class="special">(</span><span class="identifier">a</span> <span class="special">^</span> <span class="identifier">b</span><span class="special">):</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">A</span><span class="special">&gt;</span>
<span class="identifier">a</span><span class="special">:</span> <span class="identifier">Unused</span><span class="special">,</span> <span class="identifier">b</span><span class="special">:</span> <span class="identifier">B</span> <span class="special">--&gt;</span> <span class="special">(</span><span class="identifier">a</span> <span class="special">^</span> <span class="identifier">b</span><span class="special">):</span> <span class="identifier">optional</span><span class="special">&lt;</span><span class="identifier">B</span><span class="special">&gt;</span>
<span class="identifier">a</span><span class="special">:</span> <span class="identifier">Unused</span><span class="special">,</span> <span class="identifier">b</span><span class="special">:</span> <span class="identifier">Unused</span> <span class="special">--&gt;</span> <span class="special">(</span><span class="identifier">a</span> <span class="special">^</span> <span class="identifier">b</span><span class="special">):</span> <span class="identifier">Unused</span></pre>
<p>
                    </p>
                  </td>
</tr></tbody>
</table></div>
<h6>
<a name="spirit.qi.reference.operator.permutation.h5"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.complexity"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.complexity">Complexity</a>
          </h6>
<div class="blockquote"><blockquote class="blockquote"><p>
              The overall complexity of the permutation parser is defined by the
              sum of the complexities of its elements, s, multiplied by log s. The
              complexity of the permutation parser itself is O(N log N), where N
              is the number of elements.
            </p></blockquote></div>
<h6>
<a name="spirit.qi.reference.operator.permutation.h6"></a>
            <span class="phrase"><a name="spirit.qi.reference.operator.permutation.example"></a></span><a class="link" href="permutation.html#spirit.qi.reference.operator.permutation.example">Example</a>
          </h6>
<div class="note"><table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td>
<th align="left">Note</th>
</tr>
<tr><td align="left" valign="top"><p>
              The test harness for the example(s) below is presented in the <a class="link" href="../basics.html#spirit.qi.reference.basics.examples">Basics Examples</a>
              section.
            </p></td></tr>
</table></div>
<p>
            Some using declarations:
          </p>
<p>
</p>
<pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">ascii</span><span class="special">::</span><span class="identifier">char_</span><span class="special">;</span>
</pre>
<p>
          </p>
<p>
            Parse a string containing DNA codes (ACTG)
          </p>
<p>
</p>
<pre class="programlisting"><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"ACTGGCTAGACT"</span><span class="special">,</span> <span class="special">*(</span><span class="identifier">char_</span><span class="special">(</span><span class="char">'A'</span><span class="special">)</span> <span class="special">^</span> <span class="char">'C'</span> <span class="special">^</span> <span class="char">'T'</span> <span class="special">^</span> <span class="char">'G'</span><span class="special">));</span>
</pre>
<p>
          </p>
</div>
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        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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